欢迎访问ic37.com |
会员登录 免费注册
发布采购

SN8F2250B 参数 Datasheet PDF下载

SN8F2250B图片预览
型号: SN8F2250B
PDF下载: 下载PDF文件 查看货源
内容描述: 8位微控制器 [8-Bit Micro-Controller]
分类和应用: 微控制器
文件页数/大小: 133 页 / 1554 K
品牌: SONIX [ SONIX TECHNOLOGY COMPANY ]
 浏览型号SN8F2250B的Datasheet PDF文件第41页浏览型号SN8F2250B的Datasheet PDF文件第42页浏览型号SN8F2250B的Datasheet PDF文件第43页浏览型号SN8F2250B的Datasheet PDF文件第44页浏览型号SN8F2250B的Datasheet PDF文件第46页浏览型号SN8F2250B的Datasheet PDF文件第47页浏览型号SN8F2250B的Datasheet PDF文件第48页浏览型号SN8F2250B的Datasheet PDF文件第49页  
SN8F2250B Series  
USB 2.0 Full-Speed 8-Bit Micro-Controller  
3.6.4 Voltage Bias Reset Circuit  
VDD  
R1  
47K ohm  
E
C
B
Q1  
RST  
MCU  
R2  
10K ohm  
R3  
2K ohm  
VSS  
VCC  
GND  
The voltage bias reset circuit is a low cost voltage detector and can improve brown out reset condition completely.  
The operating voltage is not accurate as zener diode reset circuit. Use R1, R2 bias voltage to be the active level. When  
VDD voltage level is above or equal to “0.7V x (R1 + R2) / R1”, the C terminal of the PNP transistor outputs high  
voltage and MCU operates normally. When VDD is below “0.7V x (R1 + R2) / R1”, the C terminal of the PNP transistor  
outputs low voltage and MCU is in reset mode.  
Decide the reset detect voltage by R1, R2 resistances. Select the right R1, R2 value to conform the application. In the  
circuit diagram condition, the MCU’s reset pin level varies with VDD voltage variation, and the differential voltage is  
0.7V. If the VDD drops and the voltage lower than reset pin detect level, the system would be reset. If want to make the  
reset active earlier, set the R2 > R1 and the cap between VDD and C terminal voltage is larger than 0.7V. The external  
reset circuit is with a stable current through R1 and R2. For power consumption issue application, e.g. DC power  
system, the current must be considered to whole system power consumption.  
’
Note: Under unstable power condition as brown out reset, “Zener diode rest circuit” and “Voltage bias  
reset circuit” can protects system no any error occurrence as power dropping. When power drops  
below the reset detect voltage, the system reset would be triggered, and then system executes  
reset sequence. That makes sure the system work well under unstable power situation.  
3.6.5 External Reset IC  
VDD  
Bypass  
Capacitor  
0.1uF  
VDD  
RST  
MCU  
Reset  
IC  
RST  
VSS  
VSS  
VCC  
GND  
The external reset circuit also use external reset IC to enhance MCU reset performance. This is a high cost and good  
effect solution. By different application and system requirement to select suitable reset IC. The reset circuit can  
improve all power variation  
SONiX TECHNOLOGY CO., LTD  
Page 45  
Version 1.1  
 
 复制成功!